In recent years, video player/recorders have become very popular. Typically, there is a video head which either records or plays back the video portion of a playing tape, an audio head which performs the same function for the sound portion of the tape, an erase head, and possibly other components which engage the tape. For proper operation of the player/recorder, it is desirable that the surface portions of at least the video and audio head, and in some instances other components that contact the playing tape, be cleaned periodically.
Particularly for cassette player/recorders, this cleaning operation can be rather difficult. In a typical cassette player/recorder, there is a rectangular cassette recess into which the cassette containing the playing tape is placed. The video head and the audio head of the machine are positioned within the housing of the player/recorder, and are spaced a moderate distance away from the open cassette recess. When the player/recorder is operated, a number of guides that are part of the player/recorder apparatus engage the tape in the cassette case and move the tape outwardly into engagement with the playing/recording heads. The locations of these heads are sufficiently inaccessible so that cleaning the heads by means of some manually operated instrument is at best a clumsy operation, and can possibly damage the more delicate components.
Another problem is that the video playing/recording head is a delicate component which should be handled with a high degree of care. A typical video head is in the shape of a disc having a circumferential operating surface which engages the surface of the playing tape. On the peripheral surface of the video head, there is at least one (and in some instances a plurality) of scanning elements. The video head is mounted for rotation about a circular path that is slightly angled or canted with respect to the longitudinal axis of the playing tape. In operation, the video head is rotated at a very high rate, in the order of one to two thousand revolutions per minute, with the elements scanning the tape on each revolution. In bringing any sort of cleaning device into contact with the video head, extreme caution should be exercised in avoiding any damage to the operating elements of the video head. Also, with the video head rotating at such high speed, the torque of the drive for the video head is necessarily small, so that care should be exercised in not creating any substantial amount of frictional resistance against the peripheral surface of the head, since it is possible that such resistance would substantially reduce the rate of rotation and possibly damage some of the operating components.
A search of the patent literature disclosed a number of U.S. patents, these being discussed below.
U.S. Pat. No. 3,647,990, Eul Jr. et al, discloses a cleaning and demagnetizing device where there is a cleaning tape rotatably mounted about a spindle. A demagnetizing element is gradually moved away from the playing head by a reduction in diameter of the winding of the cleaning tape.
U.S. Pat. No. 3,761,994, Becht, shows a manually operated lever which can be moved back and forth to clean the head of a magnetic tape recording/playing unit. This lever is mounted in a cartridge which is placed in the aperture or recess of the unit.
U.S. Pat. No. 3,955,214, Post, shows a cassette housing containing a device to clean the playing head of a magnetic tape recorder/playing unit. There is a cam member rotatably mounted so as to be driven by one of the drive spindles of the unit. The cam member causes back and forth motion of an operating lever, which in turn causes a cleaning element to move back and forth across the playing/recording head.
U.S. Pat. No. 4,141,053, Kara, discloses a cassette-type cleaner for a magnetic tape recording/playback unit. In operation, the capstan of the unit engages a rubber pad which starts rotation of a gear-train which rotates a cleaning member that is in contact with the playing/recording head.
U.S. Pat. No. 4,149,206, Loiselle, discloses a device for cleaning the head of a magnetic tape recorder/playing unit, where there is a lever arm which moves a cleaning element back and forth across the head. There is an eccentrically mounted circular cam which is driven by one of the spindles of the unit to cause back and forth movement of the lever.
In some video player/recorder units, some of the operating components are placed so that the tape must be moved by the guide members a relatively large distance into the operating area of the unit to engage the operating components. Because these components are relatively inaccessible, they are particularly difficult to be cleaned effectively, and be cleaned so as not to damage the more delicate components. In view of this, it is an object of the present invention to provide a method and apparatus which can effectively and reliably clean operating components of a video player/recorder, particularly where the operating components are relatively inaccessible and susceptible to being damaged.